This paper presents the first full thermodynamic description of the hydrogen transfer between acrolein, the simplest α,β-unsaturated aldehyde, and a set of aliphatic alcohols, both primary and secondary. The vapour phase transfer hydrogenation of acrolein into allyl alcohol with various primary and secondary aliphatic alcohols used as hydrogen donors in the presence of MgO as the catalyst has been studied. Despite differentiated reactivity exhibited by these alcohols, a high chemoselectivity (>80%) to allyl alcohol has been observed for all of them. On the basis of thermodynamic calculations it has been found that secondary alcohols as hydrogen donors are more reactive than primary ones. However, ethanol or butan-1-ol have shown the highest reactivity. In their presence yields of allyl alcohol higher than 60% have been noted, which greatly exceed those predicted by thermodynamic calculations based on the following equation: acrolein + ethanol (butan-1-ol) → allyl alcohol + acetaldehyde (butyraldehyde). Although similar yields have been reported in literature, no subsequent nor side reactions have been discussed even though the attained yield cannot be accounted for by this reaction alone. As a possible explanation of the discrepancy the occurrence of a disregarded reaction, for which ΔG < 0, has been considered. It has been shown that aldol condensation fulfills these thermodynamic requirements, however, the products of this reaction are noted only at the beginning of the process and the decrease of their amount does not influence the yield of allyl alcohol.

The reaction of iodine with various metal oxides has been studied in both vapour phase (373–873 K) and in solution in cyclohexane, under anhydrous conditions. The course of the reaction has been revised in accordance with literature and experimental data. Apart from adsorbed iodine molecules ([I₂] < 200 μmol·g^–1), the presence of I^– ions ([I^–] < 50 μmol·g^–1) has been noted. IO_n^– ions have been observed only when both water and strong basic sites, such as those on MgO or La₂O₃, are present. It has been found that the strength of interaction of iodine with metal oxide increases with basicity of the oxide.

The measurements of the minimum acid strength (H_Omin) required for the initiation of cis-stilbene at 303 K and tert-butylbenzene at 313 K, 323 K and 333 K have enabled the establishment of a much more precise acid strength scale based on test reactions. H_Omin values obtained were: − 9.0 (cis-stilbene, 303 K), − 9.3, − 9.5 and − 9.9 (tert-butylbenzene, 313 K, 323 K, 333 K). The updated method was used for the determination of the acid strength of different catalysts obtained in the reaction of chlorosulfonic and sulfuric acid on different oxide carriers. It was found that the acid strength values depended on the basicity of the studied supports. For the supports treated with chlorosulfonic acid the values of acid strength were: − 11.5 < H_O ≤ − 10.8 in the case of the less basic SiO₂ and − 9.3 < H_O ≤ − 9.0 for the more basic TiO₂, Al₂O₃ and MgO. For the supports treated with sulfuric acid the acid strength was: -9.3 < H_O ≤ -9.0 for the less basic SiO₂ and TiO₂, − 9.0 < H_O ≤ − 7.9 for the more basic Al₂O₃ and − 7.9 < H_O ≤ − 6.9 for the most basic MgO. Silica treated with chlorosulfonic acid possesses higher acid strength than HZSM-5 and amorphous silicaalumina. The catalyst obtained in the modification of TiO₂, Al₂O₃ and MgO with chlorosulfonic acid were of lower acid strength comparable to Amberlyst 15 and HZSM-5 (− 9.3 < H_O ≤ − 9.0), but higher than p-xylene-2-sulfonic acid dihydrate (− 7.9 < H_O ≤ − 6.9).